The news conference will originate from NASA's Johnson Space Center in Houston at the conclusion of a meeting in which senior NASA managers, space station partners and Orbital Sciences officials will evaluate the spacecraft's readiness for flight. Cygnus is scheduled for launch Tuesday, Sept. 17, from NASA's Wallops Flight Facility in Virginia.

The briefing will be broadcast live on NASA Television and on the agency's website.

Reporters may ask questions from participating NASA centers or via telephone. To participate by telephone they must dial Johnson's newsroom at 281-483-5111 no later than 15 minutes before the start of the briefing. For those attending in person, the deadline for reporters to request credentials for Johnson is 5 p.m. EDT (4 p.m. CDT) Tuesday, Sept. 3.

During the test flight to the station, the Cygnus vehicle will test out several of its systems and capabilities. Once the space station flight control team has verified the results of these objectives, the spacecraft will be cleared to approach the station several days after launch. It will undergo a series of further tests and maneuvers and will ultimately arrive underneath the station, where the onboard crew will use the station's robotic arm to capture the cargo ship and install it on the bottom side of the station's Harmony module.

Orbital Sciences Corp. is the second of NASA's two partners taking part in the Commercial Orbital Transportation Services Program. The goal is to work with private and public companies to create two new U.S. cargo vehicles to serve the needs of the space station crew. The first company, SpaceX began its work in 2006. After a successful test flight in 2012, it began flying regular cargo missions to the station. Orbital Sciences Corp. began its work in 2008 and will begin regular missions to the space station after the demonstration flight.

To watch the briefing online, and for other NASA TV streaming video, scheduling and downlink information, visit: